Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!cbmvax!vu-vlsi!devon!paul
From: paul@devon.UUCP
Newsgroups: news.admin
Subject: Re: Sending Email to People who post to the USENET
Message-ID: <228@devon.UUCP>
Date: Sun, 1-Mar-87 14:20:17 EST
Article-I.D.: devon.228
Posted: Sun Mar  1 14:20:17 1987
Date-Received: Mon, 2-Mar-87 20:06:57 EST
References: <1354@hplabsc.UUCP>
Organization: Devon Computer Services, Allentown, PA
Lines: 55
Summary: you asked for comments...

In article <1354@hplabsc.UUCP>, taylor@hplabsc.UUCP (Dave Taylor) writes:
> BUT as far as what we're talking about here, the best solution I can 
> make is for people to have mail systems that grab not only the 
> From: address in the posting, but the Path: address too, and read the
> Path: backwards until it finds a 'backbone' that it knows (you can
> have a file containing the 10 or 15 main ones, if you want) and then
> figures out the optimal (static, alas) route to that backbone.
> 
> [  example deleted  ]
>
> 	Anyone have any comments?
> 

Yeah. Two of them.

First, the Path: line, although "newer" than the static information
from pathalias, is not necessarily correct.  Take the Path: line
in the article I'm following up to:

Path: vu-vlsi!cbmvax!rutgers!seismo!lll-lcc!pyramid!hplabs!hplabsc!taylor

While this is the path that the article took to get here, it ignores
the fact that devon (my system) talks directly with cbmvax for mail
purposes (my news feed comes from vu-vlsi).  It also ignores the fact
that cbmvax exchanges mail with seismo directly, too.

This is not necessarily a Bad Thing--routing through extra hosts.  It
would have the benefit of using more recent data to make a routing
decisison.  But (here comes the 2nd comment:) what if cbmvax exchanged
ONLY NEWS with rutgers (yeah, I know, it doesn't.  But what if it did!).
Your mail-path-parsing scheme, not knowing this, would attempt to send
mail via:

	...!seismo!rutgers!cbmvax!vu-vlsi!...

and rutgers would not be able to forward it to cbmvax.  Although my
example is not good, the point I'm making is that it would be A Bad
Idea to assume that just because news follows a given path, that mail
will be able to follow the same path.

Does all this sound familiar?  B-news 2.11, if compiled without the
INTERNET definition, uses the Path: line to generate a return route
for a reply (for reply-by-mail, not followups).  I had more mail
bounced back before I defined INTERNET here than I care to remember
(Yes, I've installed smail and defined INTERNET to news now).  Smail
may be using "older" data, but I've had *far less* troubles with
pathalias/smail generated paths than I had before using them.

- paul

-- 
Paul Sutcliffe, Jr.	    paul@devon.UUCP	(or, if you prefer:)
Devon Computer Services	    {seismo,ihnp4,allegra,rutgers}!cbmvax!devon!paul
Allentown, PA
		"I love work.  I could sit and watch people do it all day!"